With the microelectronics technology fast development, today ultra large scale integrated chip has increased its integration density up to several billion devices per chip. So far, its feature size shrank into Nanometer level, which requires several hundred manufacturing processes, among them, especially that of being able to realize the global planarization of multilayer metallization, silicon substrate, dielectric materials etc. Chemical mechanical polishing (CMP) is one of the best planarization method, which has be proved in industry for decades.
For a typical chemical mechanical polishing method, the substrate to be polished is made to contact with the polishing pad directly. At the same time, a pressure is applied to the back of the substrate. During the polishing, polishing pad is rotated with the rotation of polishing platen, while a certain pressure applied to the substrate being polished, while the CMP slurry (composed of abrasives and reactive chemical components) are distribute onto the polishing pad. Thus, there would be the chemical mechanical polishing proceeded through, on the one hand, the chemistry reaction between CMP slurry and substrate surface film and on the other hand, the mechanical function. CMP slurry is one of the most important factors which influence the CMP performance. Oxidant was usually added into the CMP slurry to tune the polishing performance according to the polishing needs.
U.S. Pat. Nos. 6,620,037 6,569,350 and 6,063,306 reported hydrogen peroxide and urea hydrogen peroxide the as oxidant in CMP slurry U.S. Pat. No. 5,954,997 reported ammonia per sulfate as oxidant in CMP slurry U.S. Pat. Nos. 680,581 and 6,068,787 reported organic or inorganic peroxide as oxidant in CMP slurry U.S. Pat. No. 5,993,686 reported ferric salt, potassium salt, ammonium salt, quaternary ammonium salt, phosphonium salt, per oxide, chlorate, per chlorate, nitrate, permanganate or persulfate as well as their mixture, ferric nitrate etc. as oxidant in the CMP slurry. U.S. Pat. No. 5,980,775 reported hydrogen peroxide, organic peroxide, inorganic peroxide and their mixture etc as the oxidant in CMP slurry. But so far, the oxidant in the CMP slurry has some problems: the capability of oxidization is not strong enough, the speed of oxidization is not fast enough or the oxidant is not stable enough in CMP slurry. Therefore there is the need to find a new oxidant that can be put into CMP slurry to realize the uniform, high removal rate low defectivity, high planarization polishing performances.